Meanwhile the Nautilus accelerated its backward movement, and running with propeller in reverse, it swept us along at great speed.

这时诺第留斯号倒退着开行，速度愈来愈快，机轮倒着转，带着我们如飞而去。

So this is cyclic forward and backward movements that the animals make with their whiskers.

所以这是动物用胡须做的循环前进和后退运动。